For this experiment I ran different frequencies through the circuit which is diagramed above. The circuit seems to have a treble roll-off effect as you can see in the graph of the amplitude response to change in frequency, as the frequency gets higher, the amplitude of the signal drops off. When you listen to white and pink noise through the circuit, the effect is the same, the higher frequencies are cut out while the lower frequencies stay constant when compared to the unprocessed signal. The capacitors I used in the circuit were what caused this amplitude drop at higher frequencies, but my results are actually quite strange as capacitors with lower values (like the 1uf ones in my circuit) in series usually act as high-pass filters instead of low-pass filters like the my results indicate.
In expanding upon my proximity guitar effect controller, I found that I could possibly make the device universal. It seems as though, what I am really designing is an extension for the potentiometers on normal instrument effects. If I could not create the necessary effects on my own, I can develop a connector that would go into a normal effects pedal so you could either plug in your on-board guitar controller via this connector (some type of multi-pin connector) or simply disconnect the device and use built-in knobs and switches on the effect. This development would allow users to use the device with any pedal but not limit themselves to one or two possible effects, but be able to plug into their entire pedalboard and at the same time maintain their pedals as traditional stompboxes. Another development I have made is attaching the device not to the guitar itself, but to the pickguard. On most guitars, the electronics are all bolted to the plastic pickguard not the actual wood of the body. By attaching my controller to the pickguard, the user can utilize my controller without having to do any major modifications to their instrument. You can buy replacement pickguards for $10 at retailers. The challenge with that design is that not all guitars have pickguards, then some modifications would need to be made to the guitar, but the concept would stay the same. The electronics would be mounted to a plastic sheet which will then be attached to the guitar.
1. In order to half the amplitude of the signal, you would have to use a voltage divider. By putting two resistors in series connected to ground and taking the output between the two resistors.
2.Capacitors changed the signal pattern by acting as filters. When you put a capacitor in series with the circuit, it acts as a high-pass filter, killing the low frequencies. When you hook it up as a bypass to ground, it acts as a low-pass filter, killing the high frequencies. When you use different values of capacitors, it will have an effect on the cutoff frequency. For example, when you are creating a high-pass filter, a higher value of capacitor will bring the cutoff frequency down.
3.The diode drastically affects the timbre of the sound by adding quite a bit of distortion. To put it into the circuit, I simply replaced the capacitors with the diodes.
1. I would like to further discuss my second idea from last week, the photoresistor-controlled onboard guitar effect. Ideally, this would work in any ambient light situation, so in reality would use proximity sensors instead of photocells. The final product would be inset into the pick-guard with cells about the size of a finger (1/2" radius). I would have a few effects, filters, distortion, etc. that would have their controls manipulated by the sensors on the guitar. Most interesting would be to have a pitch bend or vibrato connected. Ideally, you would be able to switch between the different effects you are controlling easily on the guitar. With this, you can use a finger or two to control the effects and still play with your thumb and leftover fingers. The added expression from the effects makes up for the lack of notes available to play due to the lack of fingers available to pluck the strings.
2. Realistically, I will probably have to end up using photocells as proximity sensors are very expensive. To get around this, I could calibrate it so that sensitivity is low and when the cells are picking up the most light, the effect parameters are all the way at zero, so they aren't fluctuating full-out otherwise. Also, it would be very difficult and time-consuming to create a switching system that would allow you to control many different effects and aspects, this would probably require digital to be truly efficient. I will probably end up settling with one or two filters and manipulating two things on each. The easiest way to hook it up would to have the effects not on the guitar, but on a separate box. I can put together a guitar cable and the other wires necessary into a single cable and run it all through the input jack area on the guitar (using 1/4'' and multi-pin plugs). It would be easiest to take professional pedals and simply hotwire the pots to my photocells, but I will probably end up building my own to see how small I can get them to have the possibility of putting them on the guitar itself. Also, otherwise, the project seems a little too simple.
For my electronics class here at NYU I have to create and upload weekly lab reports to share with both my teacher and the world.
Our first lab was a simple introduction to breadboards. We discovered how these highly useful pieces of plastic and metal work and the fundamentals of simple circuit construction. We were able to connect a battery and turn on an LED and put a variable resistor (potentiometer) in the circuit to adjust its brightness.
What are the conductive paths on the bread board?
The conductive paths on the bread board run all over the board. They are organized to connect in two strips down the length of each side to connect to power and in perpendicular strips down the two areas in the center of the board.
What are some easy mistakes to make with breadboards?
Some easy mistakes to make with breadboards are to connect the wrong side of the battery to the circuit, often reversing the circuit or forcing too much current through and causing smaller pieces to overheat. Another easy mistake to make with a breadboard is to connect your wires to a short center strip that is not connected to your circuit. The holes are very small and it is often difficult to see the correct holes to put your wires in. Finally, it's a simple mistake to strip your wires incorrectly. If you do not strip enough of the shield off, the wire will not make a solid connection. If you strip too much, you have a very high chance of your wires coming in contact with each other above the board, causing a short.
How can you make a button or switch out of two wires connected to the breadboard?
You can make a button or switch out of two wires connected to the breadboard by inserting two wires into the circuit and manipulating the ends not in the board. By touching the two bare ends together, you can complete your circuit manually and there you have a switch.
Post, ask/answer some questions of your own.
I have a few questions of my own:
1. If you run out of room on your breadboard, can you attach another board to extend your circuit?
Final Project Progress:
List your three favorite videos from the previous semester projects. (videos on youtube)
My favorite videos from previous semesters were:
1. Alex L's filter attached to a guitar
2. Marlon's helmet synth
3. YingYing's crackle box.
Here are some links to analog audio projects that I find interesting:
1. I have planned to build a power amplifier for my audio interface for quite some time so that I can use passive monitors that I already have instead of buying powered monitors. Here is a video of a homemade amp:
2. This is an idea for a project that uses photocells as variable resistors to control audio components. I would like to build something of this nature to connect to my guitar for greater performance opportunities.
3. Here is a link to a versatile OpAmp board that can be used for a myriad or auhttp://www.muzique.com/tech/opamp_multi.htm